1. Field of the Invention
The present invention relates to a device for adjusting height of a shoulder anchor which forms, for example, a seat belt apparatus of a vehicle.
2. Description of the Related Art
In a seat belt apparatus for constraining with a long belt-shaped webbing belt a body of a vehicle occupant sitting on a seat, a winding device for winding the webbing belt is disposed in the vicinity of a lower end portion of a center pillar of the vehicle. The webbing belt is pulled upward along the center pillar and turned down as it passes through a shoulder anchor mounted in the vicinity of an upper end portion of the center pillar. A distal end portion of the webbing belt is anchored to an anchor plate provided in the vicinity of a seat portion of the seat.
The webbing belt passes through a tongue between the anchor plate and the shoulder anchor. The seat belt apparatus is constituted in such a manner that the webbing belt is attached by the vehicle occupant gripping the tongue, pulling the webbing belt and causing the tongue to be held in a buckle device provided in the vicinity of the seat.
Of the devices and members which constitute the seat belt apparatus having the above constitution, the shoulder anchor can be formed to be slidable within a predetermined range along the center pillar with a device for adjusting height of a shoulder anchor, which device likewise forms a seat belt apparatus. As a consequence, a turning down position of the webbing belt can be adjusted.
The device for adjusting shoulder anchor height includes a plate-shaped guide rail secured to the vicinity of the upper end portion of the center pillar with a bolt or the like in a state in which the longitudinal direction of the guide rail runs substantially along the vertical direction of the vehicle, and a slider which is slidably attached along the longitudinal direction of the guide rail in a state in which the slider grips both end portions of the guide rail in the width direction thereof. The above shoulder anchor is anchored to this slider. The slider is provided with a cover and a lock pin is provided thereinside.
A part of the lock pin passes through a through-hole which is formed in the slider, and projects to a side of the slider which is opposite to a side at which the cover is disposed, that is, the guide rail side. Furthermore, a compression coil spring is provided inside the cover. A part of the lock pin enters the compression coil spring from one end thereof and an anchor pin formed on the cover enters the compression coil spring from another end thereof. Further, an inner diameter of the compression coil spring is larger than respective outer diameters of the lock pin and the anchor pin. The compression coil spring applies pressure to a flange portion formed at an outer circumference of the lock pin and urges the same in a direction of projecting toward the guide rail side.
A plurality of lock holes are formed in the guide rail along the longitudinal direction thereof. Inner circumference portions of the lock holes restrict movement of the lock pin along the sliding direction of the slider as a result of entry of the lock pin projecting from the slider into one of the lock holes. Thus, sliding of the slider is restricted. Namely, the shoulder anchor height can be adjusted by causing the lock pin to enter one of the plurality of lock holes.
Further, in correspondence with each of the lock holes, a tongue-shaped guide piece is provided at a side of the guide rail opposite to a side at which the slider is disposed. When the guide rail is attached to the vehicle, the guide piece has an inclined surface which faces downward and toward the inside in the width direction of the vehicle. Even in the state in which the lock pin has entered the lock hole, when the slider is raised, the lock pin is guided by the inclined surface to move to an end surface of the guide rail at the slider side. Thereafter, the lock pin slides on the guide rail. Consequently, the slider can be raised even when the lock pin has entered one of the lock holes. The movement of the slider is substantially limited only in a downward direction. (Incidentally, in a case where the device for adjusting shoulder anchor height is to be lowered, in the state in which movement thereof is limited, a release operation such as pressing a separately provided button or the like is required.)
An upper end portion (more specifically, the upper end portion when the guide rail is attached to the vehicle) of the guide piece is connected to a part of an inner circumference of the lock hole. The guide piece is formed by bending a portion that corresponds to the inside of the lock hole toward the side opposite to the slider side when the lock hole is formed.
In the conventional device for adjusting shoulder anchor height as described above, a heat caulk is applied as a mechanical connection between the cover and the slider in the process of manufacturing the device. The compression coil spring is assembled by manual work of workers of the like, so labor efficiency is extremely poor. Thus, a structural improvement of the device for adjusting shoulder anchor height, which will enable improvement of labor efficiency, and particularly, a structural improvement thereof which will enable automation of manufacturing by machines, is required.
In consideration of the above facts, an object of the present invention is to provide a device for adjusting height of a shoulder anchor in which assembly of each part is easy and in which automation of the manufacturing steps is easy.
According to a first aspect of the present invention, there is provided a device for adjusting shoulder anchor height of a seat belt assembly in a vehicle. The device comprises (a) a slider adapted for connection to a shoulder anchor of a seat belt assembly in a vehicle for supporting the shoulder anchor, the slider having an adjustable elevation, (b) a locking member for securing the slider so that movement of the slider is prevented, (c) a coil spring for urging the locking member in a direction for securing the slider, the coil spring having an intermediate portion, and an attachment portion for attaching to the locking member, the attachment portion having a diameter smaller than a diameter of the intermediate portion, and (d) a spring receiving portion disposed opposite the spring from the locking member, the spring receiving portion being substantially coaxially aligned with the locking member, and having a diameter larger than a diameter of the locking member.
According to a second aspect of the present invention, there is provided a device for adjusting shoulder anchor height of a seat belt assembly in a vehicle. The device comprises (a) a guide rail securable to a vehicle having a seat belt assembly with a shoulder anchor, (b) a slider attachable to the shoulder anchor, the slider being mounted on the guide rail so as to be slidable therealong, (c) a cover attached to the slider and covering at least a portion thereof, (d) an engaging member supported on the slider opposite the guide rail, the engaging member being movably supported between the slider and the cover, with the engaging member being movable to a location contacting the guide rail through the slider, (e) a regulating section formed on the guide rail for regulating slidable movement of the slider via the engaging member, (f) a substantially cylindrical anchor portion provided on each of the engaging member and the cover, the cylindrical anchor portions being approximately coaxially aligned with a direction of movement of the engaging member, (g) a compression spring having opposite ends, with one end receiving one of the cylindrical anchor portions therein, for urging the engaging member to a location contacting the guide rail, and (h) a restricting portion provided on one end of the compression coil spring for restricting deviation of the compression coil spring in a direction transverse to movement direction of the engaging member, with the restricting portion contacting an outer circumference of one of the cylindrical anchor portions.
With the device for adjusting shoulder anchor height having the above structure, the slider is guided by the guide rail to slide in a predetermined direction. However, the sliding of the slide is indirectly regulated by the regulating portion via the engaging member which comes into contact with the regulating portion. This regulation is released by movement of the engaging member against the urging force of the compression coil spring provided inside the cover covering the slider.
When the compression coil spring is assembled, the substantially cylindrical anchor portions provided at the engaging member and the cover may be caused to enter the both ends of the compression spring. An anchoring structure using such a compression spring is well known. However, in this device for adjusting shoulder anchor height, a restricting portion is provided at an end portion (at least one of both end portions) of the compression coil spring and thus the outer circumference of the anchor portion comes into contact with the restricting portion. Consequently, at least in the vicinity of the end portion at which the restricting portion of the compression spring is provided, displacement of the compression coil spring with respect to the anchor portion in a direction intersetting the movement direction of the engaging member (that is, the urging direction of the compression spring) is restricted.
Normally, when a compression coil spring is displaced with respect to an anchor portion, a compression force ceases to act evenly on the compression spring at a time of compression of the compression spring, with the result that the direction of an axis line of the compression coil spring inclines, or the compression coil spring is compressed in a deformed manner. In addition, there is a phenomenon in which a part of an intermediate portion of the compression coil spring comes into contact with a distal end portion of an engaging portion. In a case where such a phenomenon occurs, the compression coil spring is not sufficiently compressed. As a consequence, the engaging member is not sufficiently displaced, which hinders smooth sliding of a slider.
Therefore, conventionally, the position of a compression coil spring is strictly set at the time of assembly of the compression coil spring, thereby preventing an undesired displacement as described above.
On the other hand, with the present invention, because undesired displacement of the compression coil spring is restricted by provision of the restricting portion, strict positioning of the compression coil spring at the time of assembly of the compression coil spring becomes unnecessary.
With the device for adjusting shoulder anchor height having the above structure, because a ring portion which is formed by a portion in the vicinity of the end portion of the compression coil spring serves as the restricting portion, a processing cost for forming the restricting portion is cheap.
According to a third aspect of the present invention, there is provided a device for adjusting shoulder anchor height of a seat belt assembly in a vehicle, the device comprises (a) a slider connected to a shoulder anchor of a seat belt assembly in a vehicle for supporting the shoulder anchor, the slider having an adjustable elevation, (b) a locking member for securing the slider such that movement of the slider is prevented, (c) a coil spring for urging the locking member in a direction for securing the slider, the coil spring having an intermediate portion, and an attachment portion for attaching to the locking member, the attachment portion having a diameter smaller than a diameter of the intermediate portion, and (d) a plate member for moving the locking member in a direction of releasing the locking member from the slider.